Not to send outward electric waves generated by electronic components or modules for high frequency used in electric devices or information communication devices or to protect internal electronic components or modules from external electric waves, electric wave-preventing gaskets having excellent restoring force and elasticity and high electrical conductivity with a low pressing force are used.
Since having high electrical conductivity, electroconductive gaskets or electroconductive-adhesive tapes may have low electrical resistance and may have excellent elasticity to be well restored by repetitively applied force.
To manufacture such electroconductive product, Korean Patent Publication No. 2013-0106749, applied and published by the present applicant, discloses a conductive polymer foaming elastomer including a polymer foamed body in an open cell structure in which plural pores are vertically connected without a skin layer on the upper and lower sides, non-foamed conductive polymer elastic coating layers which are connected to each other by being combined by hardening a liquid conductive polymer on the upper and lower sides of the polymer foamed body and inner surface of the pores, a solderable metal thin film adhered to the non-foamed conductive polymer elastic coating layer on one of the upper and lower sides by the hardening, and a conductive elastic member adhered to the non-foamed conductive polymer elastic coating layer on another of the upper and lower sides by the hardening. Regardless of the non-foamed conductive elastic coating layer, due to the open cell structure of the polymer foamed body located therein, the conductive polymer foaming elastomer has an open cell structure and the conductivity of the conductive polymer foaming elastomer increases when the conductive polymer foaming elastomer is pressurized to the vertical direction, by decreasing the floor space index of the pores.
However, according the described above, since the metal thin film or the conductive elastic member adhered to the upper side of the polymer is adhered by the hardening of the non-foamed conductive polymer elastic coating layer, the surface of the metal thin film or the conductive elastic member becomes uneven or rough, which makes vacuum pickup difficult.
Also, when the thickness of the non-foamed conductive polymer elastic coating layer on the upper side of the polymer foamed body is small, it is impossible to obtain adhesive force enough. Then, it is difficult to provide reliable adhesion with the metal thin film or the conductive elastic member adhered thereto.
Also, since it is difficult to provide the non-foamed conductive polymer elastic coating layer having a great thickness formed on the upper side of the polymer foamed body, the surface of the upper side has pores to have an open cell structure as the open cell structure of the polymer foamed body. When being rubbed, metal powder easily separates therefrom and electrical conductivity is low.
In the above, an elastomer having electrical conductivity has been described as an example. However, since being manufactured in the same way as described above, a thermal-conductive elastomer well transferring heat has similar disadvantages.